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From epidemiologic studies in several countries, passive smoking has been associated with increased risk for lung cancer, respiratory diseases, and coronary heart disease. Since the relative risks derived from those studies are weak, i.e. relative risk less than two, we investigated whether poorer diets and less healthy lifestyles might act as confounders and be correlated with having a smoking husband on a cross-cultural basis. Characteristics of never-smoked wives with or without smoking husbands were compared between 530 women from Hong Kong, 13,047 from Japan, 87 from Sweden, and 144 from the U.S. In all four sites, wives with smoking husbands generally ate less healthy diets. They had a tendency to eat more fried food but less fruit than wives with nonsmoking husbands. Other healthy traits, e.g. avoiding obesity, dietary cholesterol and alcohol, or taking vitamins and participating in preventive screening were also less prevalent among wives with smoking husbands. These patterns suggest that never-smoked wives with smoking husbands tend to share the same less healthy dietary traits characteristic of smokers, and to have dietary habits associated with increased risk for lung cancer and heart disease in their societies. These results emphasize the need to take into account the potential confounding effects of diet and lifestyle in studies evaluating the health effects of passive smoking, especially since it is known that the current prevalence rates of smoking among men is indirectly associated with social class and education in affluent urban societies.

To study the possible association between drinking tea and lung cancer, epidemiological and experimental materials were collected from the Chinese population in Hong Kong. In a retrospective study of 200 female lung cancer patients and 200 matched controls, all subjects were interviewed concerning their eating habits, smoking histories, and lifetime exposures to environmental pollutants. Analysis of the data demonstrated an adjusted and statistically significant increased lung cancer risk of 2.7 among those who drank green tea. Several brands of tea commonly drank in Hong Kong were assayed for mutagenicity using Ames' assay. Significantly elevated levels of mutagenic activity were found to be present after metabolic activation using cell-free extracts of cecal bacteria from rats. These data suggest that further research is needed to understand the possible consequences to human health of ingestants taken at low doses but long duration over the normal lifespan, and the possible interactive effect between mutagens in tea and other ingestants and inhalants in human cancer etiology.

Studies to evaluate the effects of environmental tobacco smoke (ETS, passive smoking) often use nonsmoking wives with smoking discordant husbands. To see whether there were differences in exposures and behavior patterns among never-smoked wives with never-smoked vs ever-smoked husbands, the life-history profiles of 136 ever-married women with mean age of 59 were analyzed on 97 quantifiable variables. Overall, the results demonstrated that wives with never-smoked husbands had 'healthier' lifestyles than wives with smoking husbands. The former were better off in terms of socio-economic status, more conscientious housewives, ate better diets, and had better indices of family cohesiveness. They also fared better in variables that reflected health status with lower frequencies of the following: miscarriages/abortions, inhaling through the mouth, chronic cough, and chest X-rays. The differences were usually largest when comparing wives of never-smoked vs heavily smoking (greater than 20 cigarettes/day) husbands. The results indicate some correlates of passive smoking that can act as important confounders when evaluating health risks among families with smoking husbands.